This invention relates generally to a downhole oil well pump and more particularly to a pump which is air-operated and actuated by the oil level in the well.
It has been known before to provide a downhole oil well pump, which is air-operated and responsive to oil level in the well. An example of this is shown in U.S. Pat. No. 4,092,087, issued May 30, 1978. This device discloses a pumping mechanism using a valve 47 having a reciprocating valve member and locking means to retain the valve member in a closed position. The problem with this device is that the valve is expensive to manufacture and maintain which greatly increases the cost of the pump mechanism. It is very important that the valve mechanism be reliable since the pump is positioned in the well well below the surface. This requires that the valve operate continuously and reliably over a period of time without removal of the pump which increases the cost of pumping the well.
The oil well pump of this invention is used in wells having what is considered marginal production. These wells normally would be shut in due to the cost and difficulty of pumping the small amounts in production which they are capable of producing. In order to make production from such wells justifiable, it is necessary that an inexpensive and reliable pump mechanism be provided which will be dependable in operation in which can operate for periods of time without much maintenance and inspection.